Introduction: (Initial Observation)

All healthy people are able to identify different tastes by placing a substance in their mouth. Obviously there are sensory organs in our mouth that are able to handle complex task of tasting. We call these sensory organs “Taste Buds”. The ability to taste is our first defense that protects us from eating harmful substances. Because of the importance of the taste buds we must first know where are they located and how to protect them. In this project you will identify the location of taste buds. This by itself is the first step toward protecting the taste organs. When we know where are the taste buds we will protect them against burning, injury or damage by strong chemicals.

Skills required and practiced in this project:

• Making Observations
• Communicating Findings
• Making Inferences
• Drawing Conclusions

Information Gathering:

Find out about tongue, taste and flavors. Read books, magazines or ask professionals who might know in order to learn about the effect or area of study. Keep track of where you got your information from.

Following are samples of information you may find:

Facts:

• Our tongues have four basic types of taste buds: bitter, sour, salty, and sweet.
• Our taste buds are located in specific areas on our tongues.

Prerequisite Vocabulary

Taste

The flavor and sensation of food and liquid. (we sense flavors due to taste buds located on our tongues and that taste buds are located in special areas of the tongue.)

Taste buds

Little organs found on the tongue that sense and communicate different flavors in foods and liquids. The main types of flavors and sensations are sweet, salty, bitter, and sour.

Smell

to perceive the odor or scent of through stimuli affecting the olfactory nerves : get the odor or scent of with the nose

Principles:

• Eating would be pretty boring if we didn’t have taste buds! Everything would taste the same.
• Most insects use their mouths to taste flavors just as we do. But some insects can use other parts of their bodies to taste with, too! For example, a butterfly tastes food with its mouth and its feet. Ants can taste food with their mouths and with their antennae.
• People can only taste food and liquids with the taste buds in their mouths. But we sense flavors by using our sense of smell, too!
• We also have a few taste buds on the lips (especially salt-sensitive ones), the inside of the cheeks, the underside of the tongue, the roof of the mouth, and the back of the throat.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

The purpose of this project is to identify and locate the taste buds in our mouth/ tongue. Samples of questions to answer are:

1. Where are the taste buds located?
2. Can each taste bud identify all tastes?

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

The independent variable is the area of the tongue. Possible values are “Tip”, “front left”, “front right”, back left, back right, center, center back.

Dependent variable is the taste each area can identify.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

This is a sample hypothesis:

Taste buds are spread all over the tongue. Each taste bud can identify all different tastes.

Note that a hypothesis is just a guess based on your previous experiences or studies. After doing your experiments you may find out that your hypothesis is not correct.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment 1: Where are our taste buds located on our tongues?

Materials:

• Lemon juice
• Sugar
• Salt
• Powdered instant coffee
• Cups to label and put these food materials in
• Toothpicks
• Pencils

Introduction:

This experiment is designed to help us figure out where our different taste buds are located on our tongues. This experiment will help us to find out:

1. What are taste buds?
   Name different foods and liquids that are sweet, salty, sour, and bitter. You might write down these categories on a blackboard or piece of paper and jot down their examples.
2. Why don’t all foods and liquids taste the same?
   How do taste buds sense and communicate to us different flavors.
3. Where are the buds for particular tastes located?
   Are taste buds evenly distributed over the tongue? or certain tastes are experienced more intensely in some areas than others.

Procedure:

1. Collect and prepare the following materials:4 cups labeled and containing salt, sugar, lemon juice, and instant coffee
   Toothpicks
   Pencil
2. Look at a drawing or an image of tongue. Take time to think about how you are going to describe where we taste different flavors—tip of tongue, back of tongue, sides or edges of tongues. On the sides or edges, we can break it down to more towards the front or more towards the back of the tongue.
3. Use a toothpick to apply lemon juice to the tip, back and sides of the tongue. Think about what area of the tongue responds to the sour flavor of the lemon juice. Put a check in your results table where you think you sensed the sour flavor of the lemon juice. (Sample results table is bellow)
4. For powdered materials, you may need to lick your toothpick before you dip it into a cup to get a sample. Dip the toothpick into the powdered coffee and experiment with dabbing it on your tongue in different locations. Where do you pick up the bitter flavor of coffee? Put a check in the box on the results table where you sensed the coffee’s bitter flavor.
5. Dip the toothpick into sugar. Again, experiment with dabbing sugar on different locations of your tongue. Where do you pick up a sweet flavor? Put a check on the box on your results table.
6. Dip toothpick into salt (you may need to lick the toothpick first!) Try dabbing salt on your tongue. Where do you really pick up a salty flavor and taste? Check the box on your results table.

Experiment 2: The Effect of flavor on Taste

Introduction: Before we taste something, we often smell the flavor too. Some times our sense of small detects a flavor long before we see the food. In this experiment we want to determine if the flavor affects the taste.

You Will Need:

• Flavored hard candies
• A partner
• Notebook and pen

What To Do:

• Get a partner to do the experiment with you.
• Have one person close their eyes and hold their nose, while the other person feeds them a flavored hard candy without telling them the flavor.
• The person with the candy in their mouth should try to guess what flavor the candy is without letting go of their nose. Give them several minutes so the candy has a chance to dissolve in their mouth. This will give them enough time to detect the flavor.
• Is there any change in the taste of the candy from the beginning to the end of the experiment? Describe the tastes.

What This Means:

Much of what we perceive as “taste” is due to our sense of smell. At first, you may not be able to tell the specific flavor of the candy, just perhaps a sensation of sweetness or sourness. If patient, as the candy dissolves you can identify the specific taste. This is because some scent molecules volatilize and travel up through a “back door” – a passage at the back of the throat to the nose. Since we can only taste four different true tastes – sweet, sour, salt and bitter – it is actually smell that lets us experience the complex, mouthwatering flavors we associate with our favorite foods.

Materials and Equipment:

Please see the list of materials in each experiment.

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

Calculations:

If you do any calculation for your project, write your calculations in this part of your report.

Summery of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Make a drawing of the tongue and mark the areas based on the taste sensed in that area.

Why is there no “Answer Key”?

Such maps of our tongues do exist, but we choose not to provide one. First, there is too much individual variation (and variation over the course of your life, as you lose taste buds) for a single, accurate answer key. But primarily, we choose not to provide the “ right answers” because that would undermine the purpose of these activities, which is to communicate not so much specific knowledge as the process of doing science: observing carefully, forming hypotheses, and drawing conclusions based upon your own experimental data. A good scientist does not waste time asking questions that she already knows the answers to, and she tries mightily to avoid interpreting her data to fit a foregone conclusion.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

1. What are taste buds?

2. Where are our taste buds located on our tongues?

Share the information you gathered from doing your experiments. On what part of the tongue did we sense salty, sweet, bitter, and sour flavors?

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

How does Color effect taste?

Are your taste buds affected by your other senses?

Taste buds and red wine/cigarettes?

Taste buds and weight loss?

Why does lettuce taste like gasoline now?

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

List your References in this section of your report.

Find further information at these sites:

• That’s Tasty from U. Washington’s Neuroscience for Kids site also has links to other, more technical info about taste.
• Stick Out Your Tongue and Say Aah!
• “Making Sense of Taste”  from Scientific American
• Check out the fifth kind of taste bud that the Japanese call umami, described as the taste of meat, for which researchers have recently found molecular evidence: “Discovery Supports Fifth Taste Bud” from the University of Miami,“A taste for umami” (very technical!) from Nature Neuroscience, and “Umami: The fifth flavour”,, a very interesting article in the Toronto Star.

Other Related Activities/ Experiments

“Taste Buds”

Kinnon Himes

August 18, 1999

Brief Description of the Lesson: The main focus of this lesson is for the children to learn more about their sense of taste including what exactly are taste buds and where are they located. The goal of the lesson is to have children experiment in their groups with four types of food. They are to categorize each food into a basic taste bud group as well as determine where these taste buds are located. Also a goal of the lesson is to have the children participate in a discussion on the topic after the experiment.

Grade Level: This lesson is appropriate for sixth grade as stated in The Alabama Course of Study – Students will exhibit habits necessary for responsible scientific investigation.

Background Information: Our tongues have four different types of taste buds: bitter, sour, salty, and sweet. Out taste buds are located in specific areas on our tongues. Our bitter taste bud is in the back, our salty and sour buds are on the sides of our tongue and the sweet bud is on the tip of out tongue. Taste is actually the flavor of food and liquid and taste buds are little organs found on the tongue that sense and communicate different flavors in foods and liquids. The main types of flavors and sensations are sweet, salty, bitter and sour.

Most insects use their mouths to taste flavors as we do. Some insects can use other parts of their bodies to taste with, too. For example, a butterfly tastes food with its mouth and its feet. Ants can taste food with their mouth and their antennae.

Seventy to seventy-five percent of what we perceive as taste actually comes from our sense of smell. The odor molecules from food give us the most of our taste sensation. When you put food in your mouth, odor molecules from that food travel through the passage between your nose and mouth to olfactory receptor cells at the top of your nasal cavity, just beneath the brain and behind the bridge of the nose. If mucus in your nasal passages becomes too thick, air and odor molecules can’t reach your olfactory receptor cells. Thus, your brain receives no signal identifying the food, but no messengers can tell your brain, “This cool, milky substance is chocolate ice cream.” The odor molecules remain trapped in your mouth. The pathway has been blocked off to those powerful perceivers of smell–the olfactory bulbs.

Concepts Covered in the Lesson: Taste is a funny little word. It has to do with the kinds of flavors we experience in the foods we eat and the liquids we drink. Taste buds are little organs all over our tongues that interpret or pick up the sense of what flavors are in our food and liquids.

Materials and Equipment:

• lemons
• sugar cubes
• peanuts
• unsweetened chocolate
• paper plates
• tongue chart

Procedures: Ask the guiding questions: What are taste buds? Share information about different foods and liquids that are sweet, salty, sour, and bitter. Write down these categories on a blackboard or piece of paper and jot down their examples. Why don’t all foods and liquids taste the same? Wouldn’t it be boring if everything did taste the same? Introduce concept of little organs on our tongues called “taste buds” and how these sense and communicate to us different flavors. Where are our taste buds located on our tongues? Have students stick out their tongues and check out a friend’s. Can they see taste buds on the tongues? Which taste buds pick out salty, sour, sweet, or bitter flavors? Today, we are doing an experiment to help us figure out where our different taste buds are located on our tongues.

Today we are going to do an experiment to help us figure out where our different taste buds are located on out tongues. The materials people will get a materials tray for their group and they will begin to experiment with the different foods. The students will fill out a tongue graph as a group. We will collaborate and discuss our findings as a group.

Assessment: The tongue graph will be collected for assessment. Also during discussion I will be listening for evidence that they understand we sense flavors due to taste buds located on our tongues in special areas.

Internet Resource: www.eecs.umich.edu – this web site has useful information concerning our sensory organs.

Science Process Skills: The children used their observation and investigation skills in this activity.

 TASTING…..

Using our sense of taste makes us so HAPPY! We celebrate our holidays with foods that taste good to us, some SWEET, some SALTY, some even slightly SOUR or BITTER, but mix these flavors together and our enjoyment increases.
As soon as, even before, we are born we already love sweet flavors which makes sense because sugars are the chemicals we need for energy and growth. We are born disliking bitterness, a protection against eating poisons. Then we learn to recognize sour and salty flavors as growing babies. We can even keep many tastes in our memory and know when food is spoiled (and not to be eaten) if the taste does not match what we remember.
We relish our taste discussion and the topics it raises….
Discuss the “tastes” of holidays by the foods we associate with them – Thanksgiving, Christmas, the Fourth of July, Passover. If we switched these tastes around how would we feel? Turkey on the Fourth of July? Hot dogs for Thanksgiving? Chocolate eggs for Christmas? What if we could not taste, then every meal and snack would taste the same. Does EVERYTHING we eat or drink have a taste? I wonder how my tongue turns black when I eat blueberries and how the color goes away? After all tongues are not washable, or are they? The saliva our mouths keep creating and swallowing (10,000 gallons in a lifetime!) does the cleaning and rinsing for us.

THE TASTE DETECTOR

The body organs used for tasting are the tongue,and the palate in the mouth, but the real detectors, which are found ON the tongue, are the taste buds. When you see bumps on your tongue don’t think they are taste buds, these bumps are called papillae and the taste buds are inside each papillae, maybe a few or a few hundred buds in each one. The flavor must be dissolved in your saliva before any taste bud can handle it, then this flavor – let’s say it’s Mint Chocolate Chip – gathers in tiny, tiny puddles in the bottom of all these taste buds, the receptor taste cells detect the flavor and send the “taste signal” for the mixture (presumably a “GREAT ICE CREAM!” message) to the brain.
Different  TASTE AREAS of the tongue seem better than others at detecting certain flavors. The very tip is best at sweet things, the sides at sour, saltiness is detected all over and the buds right at the back detect bitter things. The tongue can also tell if the food is hot or cold and also the “spicy hotness” which actually causes a mild pain in the tongue.
Please take care of your taste buds by avoiding hot food and tobacco which spoil their efficiency and dull those millions of great tastes there are in the world.

Look at your tongue with a magnifying mirror or check a friend’s tongue with a magnifying glass. You can see the tiny, bumpy papillae but you’ll have to imagine the taste buds.
Describe your tongue: size, color, color and shape.
Dream up and tabulate some wonderful food mixtures that sound so good you feel your mouth watering (salivating) already. Think of some other combinations (ice cream and pickles?) that make you think of throwing up (nausea).
Try to list where different tastes come from in one slice of pizza.

TASTE TYPES CHARTING

With WARNINGS about tasting only those things the teacher indicates, not sharing straws and using a fresh straw for each taste, try this experiment.
Put a small amount of various-flavored water in each of several small, narrow-necked bottles, labeled with numbers. Set the bottles on a shelf at the students’ eye height to divert any telltale odors which may evaporate. While holding her nose, have each student use a straw to siphon off and taste a small amount of each unknown liquid, then chart the different taste characteristics for each sample. (An incidental lesson on the air pressure which permits the student to cover the end of the straw and siphon off a small amount – that wouldn’t hurt here.)

The experimental level of difficulty can be increased by substituting samples which are mixtures, or greatly decreased by skipping the nose hold.
As a World Wide Web searching exercise, have students check the AMAZING ANIMAL SENSES web site for the tasting abilities of butterflies and bees, earthworms and flies, octopuses and pigs, and rabbits and snakes.

WHAT DAY IS IT?

Here’s a tasteful story.
The parade was fun, then we hurried home for a warm drink that tasted both sweet and tart at the same time and some not-too-sweet cookies with raisins in them. Everyone at home seemed to be very busy, all of them in the kitchen bustling around. We went outside to avoid being knocked over!
We jumped in the leaf piles and collected some pine cones which we were just about to bring inside when we recognized the cars pulling up to the curb. It was Grandma and Grandad! We went up the path with them and into the house. Soon after that we all sat down to eat. I asked for white meat because that’s my favorite, then some mashed orange vegetables with a sweet taste, and purple, pickled vegetables that tasted a bit sour but tasted good, and some peas which had no taste at all until I put some salt on them.
For dessert we had a choice, I passed on the first pie and chose the yellow one, made with juice from fruit Grandad bought in the Florida islands. I liked it because it tasted both sweet and sour at the same time.
When everyone had finished eating I helped clear the dishes while the grown-ups ended their meal with that awful, bitter dark brown drink.

SCIENTIFIC RESEARCH

Scientists have measured the taste bud density of volunteers. They found that a person who is an “average taster” has about 184 taste buds per square centimeter of tongue – now that’s a lot of tasting – but some people are “supertasters” with 425 buds per sq.cm. whereas those called “non-tasters” average just 96 buds per sq.cm.